Severe Allergic Reaction
(Anaphylactic Shock)

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• Severe Allergic Reaction Overview
• Severe Allergic Reaction Causes
• Severe Allergic Reaction Symptoms
• When to Seek Medical Care
• Exams and Tests
• Severe Allergic Reaction Treatment
• Self-Care at Home
• Medical Treatment
• Medications
• Next Steps
• Follow-up
• Prevention
• Outlook
• For More Information
• Web Links
• Synonyms and Keywords
• Authors and Editors
• Related anaphylaxis articles:
  Anaphylaxis - on WebMD

Anaphylaxis - on MedicineNet

Severe Allergic Reaction Overview

Anaphylaxis is a severe allergic reaction that occurs rapidly and causes a life-threatening response involving the whole body. This reaction can lead to difficulty breathing and shock ultimately leading to death.

For an anaphylactic reaction to occur, you must have been exposed in the past to the substance that causes the reaction, called the antigen. This is called "sensitization."

• A bee sting, for example, may not cause an allergic reaction the first time.

• Another bee sting may produce a sudden, severe allergic reaction known as anaphylaxis or anaphylactic shock.

You may develop sensitivity and anaphylaxis to a substance that you have been exposed to many times in the past without a reaction, and often people don't recall the previous exposure.